Low-Cost, High-Performance Monocular Vision System for Air Bearing Table Attitude Determination

Abstract

Attitude determination is one of the most important prerequisites for the implementation of an air bearing table. In this context, computer vision is shown to be an enabling technology; a cost-effective monocular camera vision system, including hardware setup and navigation software, has been developed to determine the attitude of the air bearing table. Both infrared light-emitting diodes and filter are selected to simplify image processing, thereby maximizing the attitude update rate. A fiducial marker system uses five infrared light-emitting diodes with four in the same plane and the fifth outside the plane. This noncoplanar design not only improves the attitude determination accuracy, but also provides an element of robustness via a fiducial marker fault diagnosis and process method in case one of the light-emitting diodes is obscured by the top balance mass or is faulty. The static experimental results show that the system can provide attitude accuracy of 0.06 deg and angular velocity accuracy of $0.15\mathrm{deg}/\mathrm{s}$ with an attitude update rate of at least 10 Hz. Finally, a yaw-axis maneuver is performed to demonstrate the system performance under dynamic conditions. The developed system could be reused to support testing for other scientific space missions, which represents a major added value of this work.